A technique which detects an obstacle (for example, a pedestrian or a preceding vehicle) which exists in the surroundings of a vehicle and controls the vehicle so as to avoid colliding with the obstacle has been conventionally known.
Patent Literature 1 discloses a travelling control device provided with radar means that detects an obstacle in front of a concerned vehicle and imaging means that takes an image of an area in front of the concerned vehicle. When the travelling control device determines, from an image taken by the imaging means, that there is a possibility that a preceding vehicle exists on a lane on which the concerned vehicle is travelling, the radar means detects a reflected wave from the lane. When the reception intensity of the reflected wave is equal to or higher than a predetermined intensity, it is determined that the preceding vehicle exists.
The travelling control device determines a possibility that the concerned vehicle will collide with the preceding vehicle which exists on the lane on which the concerned vehicle is travelling. Accordingly, determination of a collision possibility is preferentially made for an obstacle which exists at a position closer to a center portion in the width direction of the concerned vehicle.